1. Field of the Invention
The present invention relates to a rim, and more particularly to a bicycle rim that has an advantageously altered structure for coupling spokes and nipples.
2. Description of Related Art
A conventional bicycle rim (1) in accordance with the prior art shown in FIG. 5 usually has a tire (2) peripherally engaged thereto when using. The conventional bicycle rim (1) comprises a series of first through holes (9) defined therein and each first through hole (9) co-axially aligns with a corresponding one of the radii of the conventional rim (1). Each first through hole (9) has a nipple (3) extending therethrough for pulling a spoke (4) that has one end adapted to be engaged to a hub (not shown) of a bicycle (not shown). An inner rim (5) is formed in the rim (1) for strengthening the structure of the rim (1). For conveniently rotating the nipple (3) to adjust the tension of the spoke (4), a series of second through holes (8) is defined in the inner rim (5) and each second through hole (8) aligns with a corresponding one of the first through holes (9). Each second through hole (8) has a plug (7) inserted thereinto after finishing adjusting the tension of the spoke (4). A lining (6) is completely applied on the inner rim (10) to prevent the high pressure air in the tire (2) from exhausting through the second through hole (8) and the first through hole (9).
However, the rim (1) should be slightly transformed when loading the weight of the rider and the bicycle, and the rim should lose its roundness. A first radius, vertical to the ground, of the rim (1) will slightly shortened and two second radii, vertical to the first radius will slightly lengthened such that the spokes (4) relative to the second radii load a greater tension than other spokes (4). However, the spoke (4) relative to the first radius is loosened and the nipple (3) connected to the spoke (4) relative to the first radius is loose relative to the rim (1). The spoke (4) and the nipple (3) relative to the first radius are tightened when the rim (1) is rotated. Consequently, all the spokes (4) are repeatedly tightened and loosened. The tension of each of the spokes (4) may be changed when the nipple (3) does not completely abut against the inner periphery of the rim (1). It is very dangerous when the spoke (4) is broken due to an improper tension.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional rim and the connection to the spoke.